Medicine and Health Sciences Commons^™

Analysis Of Indentation Loading Of Cortical Bone Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

In this study, we recorded the number of Acoustic emission (AE) hits and related AE energy during indentation fracture of cortical bone using a PAC PCI-2 card and pico sensor. A threshold value of 43dB was used to filter premature trigger due to background noise. Registered AE hits had more than one count (threshold crossing). Amplifier gain was set at 40dB with a (0.1-1) MHz band pass filter. 8mm cubes of cortical bones were indented in the longitudinal direction at constant crosshead speed of 1 mm min-1 using a large 2D, 50˚ wedge indenter. We hypothesised that signals occurring as …

Detection Of Microcracks During Bone Cutting Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during operative procedures. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occurring with continued loading; microcracking acts as a stimulus for main crack formation and has also been shown to occur during the propagation of the main crack. It has also been reported that Acoustic Emission (AE) is generated due to microcrack formation and crack growth, prior to, and during final fracture in …

An Experimental Technique For Measurement Of Heat Generated During Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack

Conference Papers

Orthopaedic bone cutting processes such as osteotomy and hip arthroplasty involve the cutting of one with the aid of various manual and powered cutting instruments including manual and powered bone saws. The extent of surgically induced bone necrosis at the point of the cutting tool and the bone is mainly due to the frictional heat generated by bone cutting. Bone necrosis has an impact on bone regeneration, and the rate of healing of the bone post operation. The threshold temperature for impaired regeneration of bone is in the range of 44°C to 47°C. Overheating also affects the sharpness life of …

Sequential Labelling And Acoustic Emission Analysis Of Damage Occurring In Cortical Bone During Indentation Cutting, Ger Reilly, Ashkan Safari, David Taylor, Brendan Mccormack

Conference Papers

When a surgeon uses a wedge shaped blade or an osteotome to cut cortical bone during an operative procedure the bone will fail by a process of microcracking and primary crack propagation. It has previously been observed that crack propagation is dependent on the direction of cutting relative to the main axis of the bone. It has also been observed that microcracks occurring during fracture release acoustic signals that facilitate real-time monitoring of a cutting process. In these novel studies, we labelled damage accumulation during cutting of cortical bone using sequential chelating dyes and we correlated recorded AE signals during …

Endostatin Modulates Vegf-Mediated Barrier Dysfunction In The Retinal Microvascular Endothelium, Brenda B. Brankin, M. Campbell, P. Canning, T. Gardiner, A. Stitt

Articles

Recent evidence indicates that the anti-angiogenic peptide endostatin may modulate some of the vasomodulatory effects of vascular endothelial growth factor (VEGF) in the retina, including reduction of blood retinal barrier function although it remains uncertain how endostatin promotes endothelial barrier properties. The current study has sought to examine how physiological levels of endostatin alters VEGF-induced inner BRB function using an in vitro model system and evaluation of occludin and ZO-1 regulatory responses. In addition, the ability of exogenous endostatin to regulate VEGF-mediated retinal vascular permeability in vivo was investigated.

Retinal microvascular endothelial cells (RMEC's) were exposed to various concentrations of …

An Investigation Of The Heat Affected Zone In Cortical Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack, Andrew Macey

Conference Papers

Surgical procedures such as osteotomy and hip replacement involve the cutting of bone with the aid of various manual and powered cutting instruments including manual and powered bone saws. Frictional rubbing between the blade of the saw and the bone results in the generation of localised heating of the cut bone and increased cutting forces (Ark et al, 1997). Overheating in localised areas can cause bone necrosis and have an impact on the rate of healing of the bone post operation and overheating also affects the sharpness life of the blade. A review of the literature indicates that work has …

Design Of A Wireless System For Patient-Hospital Communication And Result Validation In Point Of Care Testing, John Mcgrory, Owen Lynch, Eugene Coyle

Conference Papers

This paper discuses mobile phone (cell phone) and wireless applications for linking patients who manage their healthcare outside the hospital using Point of Care Testing (POCT) to hospital information systems (HIS). Certain medical conditions require patients to manage their healthcare by performing on themselves POC testing and act faithfully on the result. This raises quality control issue, as these POC samples and testing procedures are not independently overseen by professional hospital staff. In hospitals, samples taken by clinicians are validated by hi-tech computerised validation systems to ensure plausibility, before physicians rely on them. Patients in the home must often use …

Medium From Irradiated Cells Induces A Dose Dependent Expression Of Mitochondrial Changes And Bcl2 Responses In Unirradiated Human Keratinocytes, Paula Maguire, Carmel Mothersill, C. Seymour, Fiona Lyng

Articles

Exposure of unirradiated human keratinocytes to irradiated cell conditioned medium (ICCM) is known to cause a cascade of events that leads to reproductive death and apoptosis. This study investigates the effect of ICCM on clonogenic survival, mitochondrial mass and BCL2 expression in unirradiated keratinocytes. Exposure to 5 mGy, 0.5 Gy and 5 Gy ICCM resulted in a significant decrease in clonogenic survival. Human keratinocytes incubated with ICCM containing an antioxidant, N-acetylcysteine, showed no significant decrease in clonogenic survival. HPV-G cells incubated with ICCM containing a caspase 9 inhibitor showed no significant decrease in clonogenic survival when the ICCM dose was …

Ecology, Morality And Synergism, Thomas Power

Articles

This short essay looks at the views of unorthodox members of three professions. Richard Douthwaite an anti-growth economist, James Lovelock a "mythical" scientist, and Yoneji Masuda, a Japanese guru of the Information Technology age. All three assume a re-orientation of human thinking. Douthwaite's "moral society", Lovelock's "ecological society" and Masuda's "synergistic society" have little basis in reality, despite their intrinsic appeal. Despite the "high knowledge consumption" of an information age, predicted by Masuda, history teaches us that knowledge has always been used by man to gain power and not to better the lot of mankind. There is no reason to …

Combining Cytotoxic And Immune-Mediated Gene Therapy To Treat Brain Tumors, James Curtin, Gwendalyn King, Marianela Candolfi, Remy Greeno, Kurt Kroeger, Pedro Lowenstein, Maria Castro

Articles

Glioblastoma (GBM) is a type of intracranial brain tumor, for which there is no cure. In spite of advances in surgery, chemotherapy and radiotherapy, patients die within a year of diagnosis. Therefore, there is a critical need to develop novel therapeutic approaches for this disease. Gene therapy, which is the use of genes or other nucleic acids as drugs, is a powerful new treatment strategy which can be developed to treat GBM. Several treatment modalities are amenable for gene therapy implementation, e.g. conditional cytotoxic approaches, targeted delivery of toxins into the tumor mass, immune stimulatory strategies, and these will all …

Identification Of Fatty Acid Oxidation Disorder Patients With Lowered Acyl-Coa Thioesterase Activity In Human Skin Fibroblasts, Mary Hunt, Jos Ruiter, Petra Mooyer, Carlo W T Van Roermond, Rob Ofman, Lodewig Ijlst, Ronald J A Wanders

Articles

Background: Acyl-CoA thioesterases are enzymes that hydrolyze acyl-CoAs to the free fatty acid and coenzyme A (CoASH). These enzymes have been identified in several cellular compartments and are thought to regulate intracellular levels of acyl-CoAs, free fatty acids and CoASH. However, to date no patients deficient in acyl-CoA thioesterases have been identified. Design: Acyl-CoA thioesterase activity was measured in human skin fibroblasts. Western blot analysis was used to determine Type-II acyl-CoA thioesterase protein levels in patients. Results: Activity was found in human fibroblasts with all saturated acyl-CoAs from C4:0- to C18:0-CoA, with highest activity detected with lauroyl-CoA and myristoyl-CoA (C12:0 …

Gene Therapy And Targeted Toxins For Glioma, James Curtin, Gwendalyn King, Marianela Candolfi, Kurt Kroeger, Pedro Lowenstein, Maria Castro

Articles

The most common primary brain tumor in adults is glioblastoma. These tumors are highly invasive and aggressive with a mean survival time of nine to twelve months from diagnosis to death. Current treatment modalities are unable to significantly prolong survival in patients diagnosed with glioblastoma. As such, glioma is an attractive target for developing novel therapeutic approaches utilizing gene therapy. This review will examine the available preclinical models for glioma including xenographs, syngeneic and genetic models. Several promising therapeutic targets are currently being pursued in pre-clinical investigations. These targets will be reviewed by mechanism of action, i.e., conditional cytotoxic, targeted …

Biomarkers For Placental Abnormality, Cathal Mccarthy

Doctoral

Obstetrical complications including recurrent miscarriage, pre-eclampsia and intrauterine growth restriction (IUGR) affect 1%-5% of pregnant women (Younis and Samueloff 2003). Dysfunctional trophoblasts, impaired development of spiral arteries, imbalance in systems controlling the dilation and contraction of spiral arteries, placental fibrin clots and intervillous thrombosis are all possible factors that can result in an insufficient placental circulation. The combination of the hypercoagulable state of pregnancy and presence of genetic thrombophilic markets has the potential to induce placental thrombosis and cause placental insufficiency with subsequent obstetrical complications. The initial part of the research work involved examining the relationship between four common genetic …

Assessing Clinical Waste Management Performance In A Health Care Organisation, Victor Hrymak

Articles

An assessment of clinical waste management was undertaken in an Irish health care organisation. The methodology and results are presented together with recommendations.